House expansion by remodelling with the add-on of wings or rooms, completion of basement recreation rooms or attic rooms is of course well known. The closest known prior art was widely built beginning several decades ago in the "bungalow" form having a finished first floor for initial occupancy with a high pitched roof providing an unfinished attic for second floor future room space. The need for a more adequate solution to home expansion problems has existed for many years and become increasingly important with accelerating costs of building, high home loan interest rates and depressed new and used housing sales. Home builders have been faced with the dilemma of conventional construction costs exceeding the reach of the market. Growing families with the need for supplemental accommodations have been forced to resort to small initial homes which are rapidly outgrown; and are then confronted with excessive costs in attempting to remodel or in transferring to larger homes in which the total price reflects the uninterrupted inflation of the intervening years.